The present invention relates to a catalyst for the production of aromatic hydrocarbons and a process for the production of aromatic hydrocarbons using said catalyst. More specifically, it is concerned with a catalyst suitable for use in the production of aromatic hydrocarbons, comprising L-type zeolite treated with a halogen-containing compound and platinum deposited thereon, and also with a process for producing aromatic hydrocarbons from various hydrocarbons in high yield and with high efficiency using the above catalyst.
For production of aromatic hydrocarbons from aliphatic hydrocarbons, various methods have been disclosed, including a method using a highly acid zeolite, such as ZSM-5, as a catalyst (see, for example, Japanese Patent Publication Nos. 42639/1981, 23368/1983, Japanese Patent Application Laid-Open Nos. 92717/1978 and 140934/1981), a method using a basic catalyst comprising platinum deposited (see, for example, Japanese Patent Publication No. 57408/1983, Japanese Patent Application Laid-Open Nos. 80333/1984, 133835/1983 and 223614/1983), a method using a catalyst which is prepared by oxychlorinating L-type zeolite with a noble metal deposited thereon (Japanese Patent Application Laid-Open No. 168539/1985), a method using crystalline aluminosilicate with platinum and a fluoride deposited thereon (see Japanese Patent Publication No. 16781/1975), and a method in which X, Y or L-type zeolite with a Group VIII metal deposited thereon is used as a catalyst and the reaction is carried out in the presence of halogen (see Japanese Patent Application Laid-Open No. 15489/1985).
These methods, however, have various disadvantages.
For example, the method using a highly acid zeolite catalyst has disadvantages in that large amounts of decomposed gases are formed and the yields of aromatic hydrocarbons are low. The method using a basic catalyst comprising platinum deposited thereon has disadvantages in that the yields of aromatic hydrocarbons are high, but the activity is quickly decreased and thus the catalyst life is undesirably low. In the case of the other methods, the yields of aromatic hydrocarbons are not sufficiently high and the catalyst life is short.